Disruptive flicker is often observed in the case of light sources which are driven by AC voltage or alternating current or are controlled by PWM. This problem is particularly pronounced for light-emitting diodes (LEDs), since the illumination of LEDs as current-controlled component parts is substantially dependent on the impressed current and ceases virtually immediately when the current falls below a specific value (level).
In the case of lamps which are operated using AC sources, rectifiers with smoothing capacitors are generally required in order to suppress flicker, i.e. additional electronics, which is associated with additional manufacturing complexity. In addition, the probability of failure of the circuit is increased thereby. In order to effectively avoid a fluctuation in the current/voltage, relatively large capacitors generally need to be used, which take up a large amount of space.